In 2001’s The Sisterhood of the Traveling Pants, Ann Brashares introduced four best friends with whom young readers soon made fast friends: that first novel and its three sequels together have sold more than eight million copies. Brashares returns to these characters’ hometown in 3 Willows: The Sisterhood Grows, which focuses on another, younger sisterhood: three friends on the brink of entering high school. Delacorte will launch the novel with a 500,000-copy first printing and a six-city author tour. Bookshelf recently spoke with Brashares by phone.

Looking back, did the success of the Traveling Pants quartet surprise you?

Yes, I was surprised. How can you know? How can you predict? The Sisterhood of the Traveling Pants was my first book, and I didn’t know how readers would relate to my ideas and thoughts on paper. I loved writing that first book, yet I had quite a bit of fear and uncertainty when I started. What a happy surprise it is to realize that you can write things that resonate with readers and connect with them emotionally.

Was it intimidating to embark on subsequent books?

Living up to success can be intimidating. It’s so much easier to have no expectations than to have big ones. When I was writing the second Traveling Pants book, I knew that I actually had readers, and even though I didn’t know them, I had a relationship with them and I had to uphold my part. That created a certain pressure, but once I became involved with the new story and characters, those worries faded away.

What inspired you to give 3 Willows the same setting as the Traveling Pants series?

I enjoyed my time with the girls in those books and I yearned to go back, yet at the same time wanted to find a way to work around what I’d done already. I didn’t want to retread the same ground, though I was drawn to some of the same themes as in the earlier novels. I decided to create a new friendship in the shadow of the old friendship.

Why make the three protagonists of 3 Willows a bit younger than the Sisterhood friends?

The original Sisterhood characters start at 16 and grow up to be 20, and here I wanted to reach back to a slightly more innocent age, as middle school ends and high school is about to start. This is a wonderful age, when so much is in flux in terms of relationships with family and friends.

Was it a challenge to create distinct voices from those of the four original Sisterhood friends?

Developing characters is a strange thing. In the beginning they are abstract and I wonder how to move on from there. But at some moment they became real to me, and I felt like I put myself in their hands. Their voices became their own, very distinct from the earlier girls.

Is this a very different world than the original Sisterhood world?

I wanted 3 Willows to be both connected to and distinct from the earlier novels. I love the idea of connected worlds and I love writers like William Faulkner and Thomas Hardy, who go back again and again to the same setting. You find wonderful overlaps—a toe from one book edging into another. Not that I dare compare myself to those writers, of course. But I draw some inspiration from them in my small way, in terms of creating a large world and then rediscovering bits within that world. Of course there are differences between the worlds of the new novel and the earlier books. For one thing, I wanted to take a slightly more organic approach to these girls’ friendship.

Organic in what way?

The original Sisterhood characters leaned on luck and chance a certain amount to hold their friendship together—through the pants they share. In part, they relied on magic. In the new book, I wanted to give the characters no such crutch to help them along. They can’t rely on luck, but must deal with what’s real. This is a friendship they have to work for.

Though they don’t share a pair of pants, the 3 Willows friends are bonded by the willow tree cuttings they planted together on the last day of third grade. What is the significance of the willow and why did you choose it to frame your story?

I am inspired by themes of nature, but I didn’t initially include the willow theme in the story. I wanted to give these girls a central metaphor, as I had in the Traveling Pants novels. The idea of the willow wended its way into the book, but it doesn’t hold the characters together in any conscious way. A tree is such a rich metaphor in a million beautiful ways. You can consider a tree growing and consider its connectedness to all things above and under the ground. I didn’t start out with the willow, but the more I wrote about it, the more I cared about this metaphor.

Between the Traveling Pants books and 3 Willows, you wrote The Last Summer (of You & Me) for adults. Was writing for adults different than writing for teens?

Not really. The story I had thought of for that novel was not radically different. Of course the publishing worlds of adult and children’s books are very different, but in terms of writing it, I didn’t feel it was a massive departure. I’d written about teenage girls in my earlier books, and here I was writing about characters in their early twenties, so in a way it was a natural progression.

Will you write more novels for adults?

I might go back to it. I do like the idea of writing for adults, and perhaps writing about characters who are approaching my own age. I love the idea of being able to follow my whim, of writing about whatever characters suggest themselves to me. As much as I’m drawn to writing about teenage girls, I like the idea of having the freedom to branch out and write about different ages, for different ages.

Will there be more books about the 3 Willows friends?

I can imagine at least a couple more about them. This novel represents one part of their lives, but I feel that their lives are so much bigger than this book. I do see their lives expanding, outward and inward, into the future. I wrote 3 Willows with a sense that I want to connect to these characters in the long term and I do intend to go back to them, but I’m not working on another book about them yet.

What are you working on now?

I’m in the early stages writing a novel that’s pretty different from what I’ve done so far. It’s a love story first and foremost, but the canvas is a broad sweep of places and times. Part of the premise is that memory does not work in quite the way we consciously understand it to. I’m not quite sure how it will turn out, but I’m enjoying it a lot.

You’ll soon be on the road again, to promote your new novel. Do fans you meet along the way ever spark ideas for your fiction?

It’s hard, when meeting people so briefly, to get a thorough sense of them and their stories. People do tell me about their own friendships and I don’t know that I’ve used any of these stories specifically, but it does help me to have a broader sense of my readers and their lives. And I often feel an instant connection to them.

In what way?

I have spent so many hours with my characters, imagining them and writing about them. And then a reader spends time in that imagined space, and in a way it is as though we’ve spent time together. It creates a certain feeling of intimacy—with someone I’ve met only 30 seconds before. Readers sometimes tell me things that are quite personal, which I see as a natural outcome of this odd little relationship we suddenly have. I find it very interesting—and illuminating.

3 Willows: The Sisterhood Grows by Ann Brashares. Delacorte, $18.99 ISBN 978-0-385-73676-3